As bells marking the armistice hour started ringing out across Paris and in many nations hit by the four years of slaughter, Mr Macron and other leaders were still on their way to the centennial site at the Arc de Triomphe.
Trump introduced six American veterans of the Second World War and an USA eighth-grader who saved money for two years so he could attend the ceremony to honor the heroes of WWI.
The service concluded with the bugle call that was played at 11am on November 11, 1918 to signal the end of fighting on the Western Front.
Macron will pay tribute to the fallen soldiers in a speech at the Arc de Triomphe, where an unknown soldier killed in the war is buried. A reckless, shirtless lady climbed over the barricades and nearly threw herself at Trump's motorcade as it drove along the Champs Elysees, prompting the police to intervene.
Three topless protesters from radical feminist movement Femen were arrested trying to reach Trump's motorcade, although French Interior Minister Christophe Castaner said his security had "in no way been threatened".
After French President Emmanuel Macron said Europe needs to defend itself from the United States, aides said he was misunderstood.
Trump later was attending a leaders' lunch hosted by Macron.
"Patriotism is the exact opposite of nationalism: Nationalism is a betrayal of patriotism", Macron said, adding that, when nations put their interests first and decide "who cares about the others" they "erase the most precious thing a nation can have ... its moral values".
The Deputy Prime Minister said Macron failed to acknowledge all countries and focused more on anti-nationalism. But, despite the USA president branded "very insulting" his French counterpart's proposal, Mr Macron doubled down on it, arguing European allies should buy European-made materials for their defence rather than rely on the United States for them.
"The aim of the forum is to show that there are lots of forces in the global system - states, NGOs, foundations, intellectuals, companies - who believe we need a world of rules, an open world and a multilateral world", chief organiser Justin Vaisse told AFP.
Sitting several seats away was Russian President Vladimir Putin, who arrived at the ceremony separately as well.
Germany's Angela Merkel echoed the theme at a Peace Forum Macron hosted later in the day, an event that Trump skipped.
Putin told Russia's RT network after the ceremony that he and Trump spoke during a leaders' luncheon, but a formal meeting would wait until they cross paths at the G-20 Summit in Buenos Aries later this month.
Putin exchanged brief handshakes with other world leaders, but he and Trump engaged in mutual arm and back patting.
Echoing comments made by Macron, she said there was a worrying readiness by some to promote self-interest and ignore ties that have underpinned peace since the end of World War Two. At the war's end, the US had 2 million troops in Europe and another 2 million ready to cross the Atlantic if needed, a force that turned the United States into a major military power whose soldiers then fought and died again for Europe in World War II.
Trump spoke during a WWI centennial at the Suresnes American Cemetery and Memorial where more than 1,500 US military servicemen are buried.
Yesterday the US President called off a trip to the Belleau Wood battlefield and cemetery because of 'scheduling and logistical difficulties caused by the weather, ' the White House said.